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  #1  
Old 07-11-2012, 08:02 AM
Ben
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Default Co-infection with Hepatitis causes delay in HIV window period testing?

Hello Dr Sean

I am concerned about the body's production of HIV antobodies if co-infected with Hepatitis C. I have read on the internet that some people believe that if someone is infected with HIV and Hepatitis C from the same exposure or previously had Hepatitis C infection before the HIV infection, this could lead to a slow down in the body's production of HIV antibodies making the 3 month HIV antibody test unreliable (false negative) so recommend testing again at 6 months and 1 year. So please can you answer the following questions:

1) If a person is infected with HIV and Hepatitis C from the same exposure, so this one exposure results in HIV and Hepatitis C infection at the same time, do you believe that the body's production of HIV antibodies could be slowed down or delayed because of the simultaneous infection with Hepatitis C?

2) If someone already has Hepatitis C and then at a later date (say 5 months after contracting Hepatitis C) gets infected with HIV, could this scenario mean that the body's production of HIV antibodies be delayed or slowed down due to the person already having Hepatitis C.

3) I have heard that an HIV INSTI Rapid test is around 99% accurate at 6 weeks after exposure. Taking points 1 and 2 above - would a negative INSTI test 6 weeks after exposure still be 99% accurate even if the person was infected with Hepatitis C from the same exposure or was infected with Hepatitis C prior to HIV infection?

4) At 12 weeks after exposure to HIV, would a negative INSTI test be still be 100% conclusive that the person does NOT have HIV even if the scenarios in points 1 and 2 above happen and the person was infected with Hepatitis C in the same exposure as the HIV infection or previously infected with Hepatitis C before the HIV infection. Will the 3 month negative test be 100% conclusive regardless of co-infection with Hepatitis C?

Many thanks for answering my questions

Ben
  #2  
Old 07-12-2012, 09:16 AM
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Default Co-infection with Hepatitis causes delay in HIV window period testing?

Good Morning Ben

Thanks for your post.

Q1. No. The evidence seems to be that immunosupression by any cause - including HIV may occasionally cause false negative results with Hepatitis C antibody tests - but seemingly not or very rarely the other way around.

Q2. No - seems to be the same question as 1 but at a later time.

Q3. The available information suggests that the INSTI or equivalent modern third generation tests would generate the same accuracy in the presence of new or prior Hepatitis C infection.

Q4. Effectively yes, but all of us in clinical practice constantly remain vigilant for events which may not be reported accurately - so its entirely common for people either to forget events or to withhold the information for whatever reason. I have not experienced - with modern tests - a failure to diagnose HIV by 3 months in any circumstance - I have frequently experienced that in the past especiallly in the mid 80's and early 90's. The hepatitis C infection will not influence the HIV test.

Remember though that we do adopt a tailored approach to testing. About a third to one half of people infected with HIV ain western countries are also co-infected with hepatitis C. That rate will vary with different subgroups - eg injecting drug users. HIV seems to make Hepatitis C infection worse - but the evidence relating to the effect of hepatitis c on HIV is contradictory.

Modern Hepatitis C tests - thrid generation antibodies, antigen and also qualitative PCR will allow us to accurately diagnose Hepatitis C in a reasonable time frame - and because of the fact that hepatitis C is common in the HIV group, we are always on the look out for it.

best wishes, Sean
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Old 07-12-2012, 10:11 AM
Ben
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Thank you Dr Sean for your reply. This has put my mind at rest that the 6 week INSTI test is still greater than 99% accurate even with Hep C infection and that the 12 week INSTI test is 100% accurate even if one is co-infected with Hep C.

I have just 2 other follow up questions. Does the same apply to Hep A and B - i.e. Would Hep A or B effect the results of a 6 week and 12 week INSTI test? Would the 6 week and 12 week INSTI tests still have the same accuracy even if co-infected with Hep A and B? or even Hep A, B and C?

Also, with regard to your response in question 4 - do you mean that a 12 week INSTI test is definately 100% conclusive, but only if the patient is telling the truth regarding their history; like the date of last exposure etc. So if a patient was HIV negative before their last exposure and if they are telling the truth that their last exposure was 12 weeks prior to the INSTI test and nothing has happened in-between then this would mean that the negative result is 100% conclusive regardless of any sort of Hepatitis co-infection?

Thanks you and sorry for my long winded approach!
  #4  
Old 07-13-2012, 04:58 PM
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Hello,
I will take over this time. I will answer each of your questions in red, here as follows:

I have just 2 other follow up questions. Does the same apply to Hep A and B - i.e. Would Hep A or B effect the results of a 6 week and 12 week INSTI test? There is no evidence that that is the case. Therefore the answer is no.Would the 6 week and 12 week INSTI tests still have the same accuracy even if co-infected with Hep A and B? or even Hep A, B and C? Yes, they would.

Also, with regard to your response in question 4 - do you mean that a 12 week INSTI test is definately 100% conclusive, but only if the patient is telling the truth regarding their history; like the date of last exposure etc. So if a patient was HIV negative before their last exposure and if they are telling the truth that their last exposure was 12 weeks prior to the INSTI test and nothing has happened in-between then this would mean that the negative result is 100% conclusive regardless of any sort of Hepatitis co-infection
Exactly, that is what my colleague Dr Sean means.

Best wishes,
Josť
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  #5  
Old 07-13-2012, 05:34 PM
Ben
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Thank you very much for your response Dr Jose. I have just one other thing that is worrying me with regard to something Dr Sean said in his reply. In his reply he mentioned this:

"Remember though that we do adopt a tailored approach to testing. About a third to one half of people infected with HIV ain western countries are also co-infected with hepatitis C. That rate will vary with different subgroups - eg injecting drug users. HIV seems to make Hepatitis C infection worse - but the evidence relating to the effect of hepatitis c on HIV is contradictory"

As my origional question was regarding HIV testing being affected by the presence on Hep C, I was a bit confused by the above, especialy the bit - 'but the evidence relating to the effect of hepatitis c on HIV is contradictory'. Does Dr Sean mean that if someone has already tested positive for HIV, so has currently got both HIV and Hep C the evidence relating to the effect of hep c on HIV is contradictory. So he is therefore referring to someone who is already infected with hep c and hiv and NOT talking about the affect that Hep C may have in delaying the body's production of HIV antibodies and the HIV test window period being contradictory?

Thanks for your response and once cleared up I promise I will not bother you guys again!

Thank you both

Ben
  #6  
Old 07-15-2012, 05:34 PM
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Default HIV - coinfection with hepatitis causes delay in HIV window period testing

Hello Ben

[QUOTEDoes Dr Sean mean that if someone has already tested positive for HIV, so has currently got both HIV and Hep C the evidence relating to the effect of hep c on HIV is contradictory.yes So he is therefore referring to someone who is already infected with hep c and hiv and NOT talking about the affect that Hep C may have in delaying the body's production of HIV antibodies and the HIV test window period being contradictory?yes
][/QUOTE]

best wishes, Sean
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